Piston diaphragm having tangential corrugations



N9v. 5, 1929. H. c HARRISON 1,734,624

PISTON DIAPHRAGM HAVING TANGEI'ITIAL CORRUGATIONS Filed April 16, 1926 2 sheets-sheet 1 ample as disclosed'in an application,

'Panarea 5', 192e UNITED STA-TES PATENT OFFICE HENRY c. mnIsON, or TORT WasHrNGTON, NEW YOEx, assreNoE TO BELL TELE- rnoNE LABORATORIES, INCORPORATED, OE NEW YORK, N. Y., a CORPORATION or Yom:

`rrsxToN* mman HAVING TANGENTIAI.V OoanrreaTrONs application mea Api-u 1s,

This invention relates to diaphragms of the so-called piston or plunger type, such .for exl Seriall No. 33,619, tiled May 29, 1925,l of which the present application is a continuation in part.

It is the gieneral object of. this invention to provide a iaphra which when usedin acoustic devices w11 respond accurately to and reproduce truly and without rattle all frequencies within 'the normal audible range.

In accordance with the general features of this invention, there yis provided a piston or plunger type diaphra with low series elasticity, that is low e asticity between the 1 5 moving plunger and a stationary housing or frame to whichthe periphery of the diaphragm may be secured.

' In a specific embodiment of this invention, a diaphragm stiiened over the greater portion of'its area is rovided at its periphery with a concentric exing area -produced by means of tan entially arranged corrugations extending su stantially per endicular to the vradii drawn to the inner en s of the corrugations. Such corrugations maybe made to form flexing lines of low elasticity but with stiiened areas havin anatural period Well above that of the aufble range. Referring-to the drawings: Fig. 1 is a side view of a piston having tangential corrugations;

ldiaphragm Fig. 2 is a section v1ew of Fig. 1 ythrough l, the center; f

Fig. 3 is a side view of a piston diaphragm having tangential corrugatlons and a spider driving member Fig. 4 is a section view of Fig. 3 through l the center ;l

. F1 ton diaphragm having tangentiallv Fig. 5 is a section view through the center of two piston diaphragms 4having tangential corrugations mounted in a housing to form a tight chamber between them; y

6 is a side'view of an annularpis`4 corru-L gated portions extending rombo edges;

Fig. 7 is a section view throu h the center of an acoustic mounting for aiaphragm of v the type shown in Fig.6;

Fig. 8 is a section view through the centerI of a phonographreproducer employing apis- 192e. seriarNo. 102,454.

E9n diaphragm having ltangential corrugaf lons; a

Fig. 9 is a section view through the center of a' horn type loud speaking receiver employlng a piston diaphragm having tangential corrugations;

Fi 10 is a section view through the center o a pipe expansion joint employing tan- V gential corrugations;

Fig: 11 is a section view through the cen-ter of a diaphragm iston having tangential cor- Fig. 1'5 is a sectlon view of Fig. 14 through the center.

Referring to Figs. 1 and 2, the central porn tion 10 is conical to secure stiffness and the annular portion 11 surrounding the central portion is tangentially corrugated to secure iiexibility and the outer edge 12 is iiat to provide a clamping rim or annulus.

Figs. 3 and 4 are side and section views, respectively, of a modified design ofthe piston dlaphragm having a central portion 10 employing a plurality of concentric corrugations to secure stiffness, a tangentially corrugated annular portion 11 to secure flexibility, an outer fiat edge 12 to provide a convenient clamping rim, and a driving spider 'of Fig. 12 through member 13 with a plurality of radially eX- tending arms 14 for making connection with the piston portion 10. The spider member in this design is employed as a part of the coupling between the diaphragm and the driving element. This coupling may be designed as a mechanical transmission line according to the methods shown in my copending application Serial No. 33,619, iiled May 29, 1925.

Fig. 5 shows an application of two piston diaphragms 17 and 18 mounted in a housing 19 1n such manner that the'space between them forms a tight chamber and permits their being' used for the variableelement in such devices as a thermometer, barometer or other similar device when the chamber 2O is filled with the appropriate fluid. An advantage of this type of diaphragm in such a device is that it permits a large amplitude of movement.

vAn annular type of piston diaphragm with tangentially corrugated annular supporting portions at each edge and suitable mounting for its use in an acoustic vdevice is shown in Figs. 6 and 7. The annular piston portion 10 is supported by the outer tangenti-ally corrugated portion 11 and the inner tangentially corrugated portion 15. The corrugated portions have clamping rims 12 and 16 by which the diaphragm is held in its housing. The coupling member for attaching the driving element tothe diaphragm is shown by the spider 13 and its plurality of radial arms 14 and it is similar to the driving member shown in Figs. 3 and 4. The mounting for such an annular piston diaphragm is shown in Fig. 7 and consists of a housing member'21 and an internal member 22. These two members form a tight annular chamber 23 in frontof one side of the diaphragm and direct the vibrations produced by the diaphragm in this chamber through its passage towards the mouth of a horn (not shown). The crosssection area of the chamber 23 immediately in front of the diaphragm and its rate of change in cross-section is such as to properly load the diaphragm and transmit sound to the mouth of the horn Without unnecessary losses as described in my prior application referred to above.

An application of a piston diaphragm employing tangential corrugations to a phonograph reproducer is shown in Fig. 8. The diaphragm 24 is mounted in a siutable housing or sound box 25 and is connected to a suitable stylus arm 26 through appropriate coupling members.

application of a piston diaphragm employing tangential corrugations to a horn type receiver or loud speaker is shown in Fig. 9. The diaphragm 27 is mounted in the housing or sound box 28 and is coupled to a driving element 29.

An expansion joint for connecting pipe may be readily made by employing a sheet of material having an annular portion tangentially corrugated and having mounting rims on each edge. This is shown in Fig. 10 in which the tangentially corrugated annular member 30 is attached to the adjoining ends of two pieces of pipe 31 and 32. The fiexibility of the annular member 30 permits considerable longitudinal movement.

An application of a diaphragm piston hav- .ing tangential corrugations is .shown in Fig.

11. The diaphragm Apiston 33 is mounted in the housing and connected with a rigid piston member 35. This arrangement is applicabley to certain pum or engine devices operating upon or by a uid.

The application of a tangentially corrugated fiexing member to a large direct acting type loud speaker is shown in Figs. 12 and 13. The tangentially corrugated annular supporting member 36 is attached at its outer periphery to the periphery of the cone 37 and at its inner edge to the mounting member 38. The tangentially corrugated member, which may be readily flexed, thus supports the cone in a manner to afford minimum resistance to its vibration asa Whole, or piston fashion. The driving element A39 is mounted on the main supporting member 38 and attached to the cone 37 in any'suitable manner.

An annulus of tangential corrugations may be applied to the outer area of the cone as is shown in Figs. 14 and 15. In this arrangement the tangential corrugations 40 are directly applied to the outer edge of the material of which the cone 41 is formed. The rim j ust beyond the corrugated annulus is clamped in the rigid ring 42 which in turn is mounted on the support 43.

l/Vhen used in an acoustic device, the small areas between the flexing lines or corrugations are designed to have a critical frequency above the range important in speech and music and thus eliminate the usual rattle taking place in many types of diaphragms. The' tangentially corrugated area makes it possible for the diaphragm to vibrate as a piston through a relatively large amplitude which is desirable in most cases, whether the diaphragm is used in acoustic devices or as a diaphragm piston in a pump, engine, or other mechanical device where piston diaphragms are applicable.

While it is preferred to have the outer corrugations of the diaphragm tangential to the inner portion it is Within the scope of the invention to var their direction so long as their function of ending flexibility is not destroyed, as would be the case if the direction were radial.

What is claimed is:

1. An elastic vibrational element having a corrugated portion, the corrugations of said portion forming like angles with radii at the periphery of said element.

2. An elastic vibrational element comprising a stifenedcentral portion, and an annular corrugated portion, the corrugations in said annular portion forming like angles Wit-l1 radii at the periphery of said element.

3. An elastic vibrational element comprising a rigid portion and a flexible portion said flexible portion consisting of straight line corrugations approximately tangential to the periphery of said rigid portion,

4. An elastic vibrational element having a stifl'ened circular central portion surrounded by a corrugated annular portion whose corrurgations are tangential to and converge adjacent to each other along the periphery of the said circular central portion.

6. In an acoustic diaphragm, a stiiened portion and an annular flexible portion, the width of the flexible portion being less than the width of vthe stii'ened portion, the said flexible portion being tangentially corrugated to form small areas which have a critical frequency above the range important in speech and music. 4

7. vInan acoustical device, a diaphragm provided with. a stifened portion and with a ii'exible peripheral portion 'formed ofa plurality of tangential corrugations 'non-resist# ant to. vibrations perpendicular to the plane of the diaphragm but resistant to vibrations' parallel to that plane, said stiifenedv portion occupying the major portion of the diamet'er of the diaphragm.

8. In an acoustical device, a diaphragm provided with astiffened .central area and with a flexible peripheral area comprising a plurality of straight linetangential corrugato radii drawn tions extending substantially perpendicular to the inner ends of the corrngations. i 9.` In an acoustical'device a diaphragm provided with a stiifened portion, and with a flexing lportioncomprising a plurality of straight line corrugations non-resistant to vibrations perpendicular to the plane of the diaphragm but resistant tp vibrations paral- Vlel to that plane.

10. In an acoustical device, a diaphragm comprising a fiat peripheral clamping por-4 tion, a centrally curved stiifened portion, and

an intermediate iexible portion comprising -a, plurality of corrugations extending substantially tan entially* to the central vstifle .cned portion, t e corrugations being substantially non-resistant to forces to the plane of the diaphragm ut highly resistant to forces parallel' to that plane.

A 11. In an'acoustical device, a diaphragmv comprising a flat peripheral rtion, a dished centralstiifened portlon an an annular -intermediate portion of closely adj acent corrugations, means for supporting the diaphragm width and depth Athey approach the points phra at 1tslat portion and means for driving t le central portion.

13, In an acoustical having a peripheral portion, a stiifened central portion, and an intermediate flexible portion comprising a plurality of corrugatlons forming like angles with radii extending through the periphery ofthe stifl'ened portion, means for supporting the diaphragm along the peripheral portion, and driving means attached to the stiiened portion of the diaphragm.

14. In'an acoustical device, adiaphragm comprising a stillened central portion, an

'outer portion, and an intermediate portion formed with alternate elevations and depressions providing a large number oflmes of vHex-ure disposed at angles less than straight angles tointersecting radii of the diaphragm. 15. In an acoustical device, a diaphragm comprising a stiiened central portion, an outer portion, and an intermediate; portlon comprising 'a1 plurality of lon itudinally stifened sections, each sectioni eing disposed at an angle less than a straight angle to intersecting radii of the diaphragm, said sections having lines of iexure between each other and being of a length greater than the distance between the outer edge of the cen-y tral portion andthe outer edge of the intermediate portion. 16,. In an acustical device, a dlaphragm having an outer portion, aiI central portion,

and an intermediate portion so shaped as to device, a diaphragm i' of tangenc ,.means'for Vsupporting the diabe more flexible than the central portion or Y theouter portion, means for supporting the diaphragm along the outer portion, and driving means connectedwith the central portion vat. points removed from the Acenter thereof. v

In Witness whereof, I hereunto subscribe my name this 15th day of April, A. D. 1926.

: HENRY C. HARRISON.

erpendieular i at the-.'ilat portion and driving means ati tached tothe s tifenedportion' of the diation', and-an annular intermediate portion having'corrugations substantially tangential the central portion anddimini'shing in 12.111V combination, al diaphragm ompr'is.' ing a curved central portion, a ilat outer por-- DB'SCLAI'M ER 1,734,624-I`Henry iU. -Harrison, Port Washington, N. Y. PIsToN DIAPHRAGM- HAVING vTANtuelmmi. CoRRUGA'rIoNs. Patent dated November 5, 1929. Disclaimer iled'June 9, 1930, by the patentee and the assignee, by mesme assignments, Western Electric Company, Incorporated. Hereby disclaim from the scope of said claim 11 of said Letters Patent any and all acoustical devices other than those in which the diaphragm driving means is lease enter the disclaimer in the following Words-i. e., in claim 11, at the end thereof, add at points removed from the center thereof.

[Oficial Gazette, June 24, 1930.] 

